1. Field of the Invention
The present invention relates to a vehicle seat which is provided with a system for facilitating promoting of blood circulation in the lower limbs of an occupant sitting on the vehicle seat for many hours, thereby facilitating relieving of fatigue of the occupant.
2. Description of the Related Art
In a vehicle seat, a fatigue reduction function is required as one of various functions of the vehicle seat. As a fatigue reducing means, there is proposed a fatigue reducing means which is employed in a vehicle seat having an air bag housed within a lumbar support portion of a seat back and is configured to control lumbar supporting pressure (applied to an occupant sitting on the seat by the air bag) against the occupant on the vehicle seat by supplying of air to the air bag and sucking of air from the air bag, thus facilitating relieving of fatigue of the occupant (Japanese Patent Application Laid-Open No. Hei. 7-313293).
In the vehicle seat, unless the occupant feels fatigue, switching of the operation of the air bag is not performed by the occupant, so that fatigue reduction is hard to be timely performed.
In order to address this problem, there is proposed a vehicle seat provided with a fatigue relieving system which includes a detection means provided in a seat back of the vehicle seat for detecting variation in the angle of the pelvis region of an occupant on the seat during driving of a vehicle and an occupant's body-motion promoting means provided in the seat back of the vehicle seat for vibration-pressing the pelvis region of the occupant on the basis of a value of variation in the angle of the pelvis region (Japanese Patent Application Laid-Open No. 2005-185373).
In the vehicle seat, the fatigue relieving system may fail to suitably increase an amount of blood circulation. At this time, if the occupant's body-motion promoting means is operated with increased power, an adverse effect is easy to be exerted on a posture of the occupant on the seat during driving of the vehicle, or the occupant on the seat tends to feel a feeling of physical disorder, so that there is a possibility that a fatigue reduction effect will not be provided to the occupant.